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The KNX functionality of CoolMasterNet is fully described in: KNX Module Guidelines (PDF)

KNX module installation and activation

Physical connection of CoolMasterNet to KNX bus (TP physical layer) is made with "CoolAutomation KNX extension module", further referenced as KNX module. KNX module is pre-installed inside CoolMasterNet body by CoolAutomation. Once KNX module is installed it should be activated. Run line command to check if KNX module is already activated.


L1: DK Master U00/G00 myID:0B
Tx:2/2 Rx:2/2 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L2: Unused
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L3: KNX Physical Address:Not Assigned
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L4: Unused
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L5: Unused
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L6: Unused
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0
L7: Unused
Tx:0/0 Rx:0/0 TO:0/0 CS:0/0 Col:0/0 NAK:0/0

The trace above corresponds to the activated KNX module. Otherwise, below activation command is required.

>line type L3 KNX

OK, Boot Required!

Now KNX module is ready for operation and can be connected to KNX bus. Mind the polarity - it is essential for KNX bus.

KNX group address concept

KNX bus is usually implemented as a decentralized system. Decentralized management is implemented within the devices, they are communicating directly to each other without recourse to hierarchy or network supervisory. The communication between KNX communication objects (sensors and actuators) is made with telegrams sent to group addresses. The group addressing is based on the exchange of data coded with common rules between communication objects. Actuators can listen to several group addresses. Sensors however can only send one group address per telegram.
When setting the group address via ETS, it can be selected as a “2-level” (main group/ subgroup) or “3-level” structure (main group/middle group/subgroup). The level structure can be changed in the project properties of each individual project. The group address 0/0/0 is reserved for so-called broadcast messages (telegrams to all available bus devices).


Simple example

A simple installation shown above consists of a common KNX panel, CoolMasterNet with KNX module and power supply. This is a most simple but yet comprehensive example of the CoolMasterNet KNX based system. In real world installation can include a dozens of panels and a lot of other devices, but still integration principle will be the same.

  • First, ETS should be used to create group addresses for communication objects provided by KNX panel. Let's assume following group addresses were created:
Object Name Object Function Group Address R/W Data Type
Switch object A Push button 1 1/0/1 W 1 bit {1.001} DPT_Switch
Setpoint Temperature Output Control 1/0/4 W 2 bytes float {9.001} DPT_Value_Temp
Setpoint Temperature Input Presentation 1/0/5 R 2 bytes float {9.001} DPT_Value_Temp
  • Next, Indoor Units list should be retrieved from CoolMasterNet:

L1.001 OFF 26C 28C Top Heat OK # 0
L1.002 OFF 24C 24C Med Heat OK # 0

In this example KNX panel will control Indoor Unit L1.001

  • Finally, communication objects have to be linked with CoolMasterNet functions.

Link Push button 1, it's group address is 1/0/1, with Indoor Unit L1.001 onoff function:

>knx group 1/0/1 onoff < L1.001


Link Setpoint Temperature Control (up/down buttons), it's group address is 1/0/4, with Indoor Unit L1.001 Setpoint (ST) configuration function:

>knx group 1/0/4 ST < L1.001


Link Setpoint Temperature Presentation (group address 1/0/5) with Indoor Unit L1.001 Setpoint (ST) feedback function. This time telegram will be sent from CoolMasterNet to KNX panel, that's why we put > instead of < like in previous commands.

>knx group 1/0/5 ST > L1.001


Read overall linkage status:

>knx group

G000:1/0/1 [ On/Off ] < L1.001
G001:1/0/3 [ Set temperature ] < L1.001
G002:1/0/4 [ Set temperature ] > L1.001